Squashing JMX warnings on jetty startup

jetty-server/src/main/java/org/eclipse/jetty/server/Server.java

@@ -162,7 +162,7 @@ public class Server extends HandlerWrapper implements Attributes
     /**
      * @return Returns the connectors.
      */
-    @ManagedAttribute("connectors for this server")
+    @ManagedAttribute(value="connectors for this server", readonly=true)
     public Connector[] getConnectors()
     {
         List<Connector> connectors = new ArrayList<>(_connectors);

jetty-server/src/main/java/org/eclipse/jetty/server/handler/ContextHandler.java

@@ -381,7 +381,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
      * @return Array of virtual hosts that this context responds to. A null host name or empty array means any hostname is acceptable. Host names may be String
      *         representation of IP addresses. Host names may start with '*.' to wildcard one level of names.
      */
-    @ManagedAttribute("Virtual hosts accepted by the context")
+    @ManagedAttribute(value="Virtual hosts accepted by the context", readonly=true)
     public String[] getVirtualHosts()
     {
         return _vhosts;
@@ -1394,7 +1394,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
      * @see <a href="http://jcp.org/aboutJava/communityprocess/final/jsr154/index.html">The Servlet Specification</a>
      * @see #setWelcomeFiles
      */
-    @ManagedAttribute("Partial URIs of directory welcome files")
+    @ManagedAttribute(value="Partial URIs of directory welcome files", readonly=true)
     public String[] getWelcomeFiles()
     {
         return _welcomeFiles;

jetty-server/src/main/java/org/eclipse/jetty/server/handler/HandlerCollection.java

@@ -66,7 +66,7 @@ public class HandlerCollection extends AbstractHandlerContainer
      * @return Returns the handlers.
      */
     @Override
-    @ManagedAttribute("Wrapped handlers")
+    @ManagedAttribute(value="Wrapped handlers", readonly=true)
     public Handler[] getHandlers()
     {
         return _handlers;

jetty-webapp/src/main/java/org/eclipse/jetty/webapp/WebAppContext.java

@@ -688,7 +688,7 @@ public class WebAppContext extends ServletContextHandler implements WebAppClassL
      * @see #setSystemClasses(String[])
      * @return Returns the systemClasses.
      */
-    @ManagedAttribute("classes and packages given priority by context classloader")
+    @ManagedAttribute(value="classes and packages given priority by context classloader", readonly=true)
     public String[] getSystemClasses()
     {
         if (_systemClasses == null)